Notice doctor cuddling new arrival (6)
I believe the answer is:
advent
'arrival' is the definition.
(advent is a kind of arrival)
'notice doctor cuddling new' is the wordplay.
'notice' becomes 'ad' (both can mean an advertisement).
'doctor' becomes 'vet' (vetting is a kind of doctoring).
'cuddling' means one lot of letters goes inside another (inserted letters are cuddled or held).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'vet' placed around 'n' is 'vent'.
'ad'+'vent'='ADVENT'
(Other definitions for advent that I've seen before include "when the Church year begins" , "The season leading up to Christmas" , "Time approaching Christmas" , "Pre-Christmas period" , "Arrival of important person or event" .)